Rice husks are a byproduct of rice production. Rice husks are primarily made of silica, carbides, or nitrides of silicon, which offer protection to the rice kernels as they grow. The rice husks also contain an organic polymer called lignin, which gives a distinctive yellowish color to the husks. After harvesting, e.g., for use as a food, the rice is separated from the husks.
Currently, the majority of rice husks are incinerated at great expense, e.g., in fuel and carbon footprint. Some additional usages of rice husks include as an additive to concrete, housing in some third world countries, production of sandcrete from rice husk ash, and the manufacture of shoes, to name a few.
Rice husks have also been used in the production of light weight foam-entrained composite partition wall. Typically, the composite partition wall includes exterior panels and interior core materials. The exterior panels are obtained from mixing cement, sawdust, rice hull, fly ash, fireproof low-alkali mesh fabric, galvanized iron wire mesh, a water-reducing agent, bentonite, acrylate copolymer emulsion and water.